Without delay, let's solve this. We've got 28 and we will be multiplying it by 20, that is, adding 28 to itself 20 times.
Step 1: 0 + 28 = 28
Step 2: 28 + 28 = 56
Step 3: 56 + 28 = 84
Step 4: 84 + 28 = 112
Step 5: 112 + 28 = 140
Step 6: 140 + 28 = 168
Step 7: 168 + 28 = 196
Step 8: 196 + 28 = 224
Step 9: 224 + 28 = 252
Step 10: 252 + 28 = 280
Step 11: 280 + 28 = 308
Step 12: 308 + 28 = 336
Step 13: 336 + 28 = 364
Step 14: 364 + 28 = 392
Step 15: 392 + 28 = 420
Step 16: 420 + 28 = 448
Step 17: 448 + 28 = 476
Step 18: 476 + 28 = 504
Step 19: 504 + 28 = 532
Step 20: 532 + 28 = 560

So, 28*20 = 560